The present invention relates generally to superconductive coils.
As is known, these devices require for operation a cooling system in order to keep the superconductor from which the coil is made below its critical temperature.
Conventional cooling systems use fluids which change their state, such as liquid helium, in order to reach and maintain the low temperatures needed to ensure the superconductive behaviour of the coil material. This gives rise to certain safety problems associated with the overpressures which are generated in the cryostat in the so-called “quench” condition (namely the transition from superconductor to normal conductor) together with costly maintenance due to the need to replenish the evaporating fluid.
One object of the invention is therefore to provide a coil which is able to overcome the problems associated with the use of state-changing fluids for cooling the superconductor.
This object is achieved by means of a coil as defined in the claims which follow.